[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-150657-en":3,"doc-seo-150657-105":29,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":11,"language":21,"language_code":22,"site_id":23,"html_lang":22,"table_of_contents":24,"faqs":25,"seo_title":26,"seo_description":14,"update_tm":27,"read_time":28},150657,2336475104362,"Mali","https://ap-avatar.wpscdn.com/avatar/22000c4c46a41b752dd?x-image-process=image/resize,m_fixed,w_180,h_180&k=1786595829695023868",8,"Research & Report","Two-Stage Solid-Phase Transition of Cubic Ice to Hexagonal Ice - Structural Origin and Kinetics","Cubic (Ic) and hexagonal (Ih) ice coexist over an unusually broad low-temperature range of 150–240 K, yet the microstructural origin of this behavior remains unclear. By combining global sampling with a machine-learning potential using the stochastic surface walking-neural network approach, the study identifies key metastable intermediates during the Ic-to-Ih transition as low-energy ice defects, including vacancies, heterophase junctions, and stacking faults. Vacancy defects enable the lowest-energy Ic-to-Ih pathways and initiate fast Ih nucleation, with vacancy migration (48 kJ/mol barrier) as the rate-determining step for Ih growth.","Article  \n Cite This: J. Phys. Chem. C 2018, 122, 29009−29016 [pubs.acs.org/JPCC](pubs.acs.org/JPCC)  \n Downloaded via FUDAN UNIV on January 1, 20 19 at 1 1:04:35 (UTC) .  \nSee [https://pubs.acs.org/sharingguidelines](https://pubs.acs.org/sharingguidelines) for options on how to legitimately share published articles.  \nTwo-Stage Solid-Phase Transition of Cubic Ice to Hexagonal Ice: Structural Origin and Kinetics  \nShu-hui Guan,†,‡ Cheng Shang,*,‡ Si-Da Huang,‡ and Zhi-Pan Liu *,‡†Shanghai Academy of Agricultural Sciences, Shanghai 201403, China  \n‡Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China  \n*S Supporting Information  \nABSTRACT: Two most known ice phases, cubic (Ic) and hexagonal ice (Ih), are observed to coexist over a surprisingly broad low temperature range (150−240 K) in ice particles, the origin of which, despite great efforts devoted to revealing the ice microstructures in experiment, remains largely unknown. Here by combining global sampling with machine learning potential, the stochastic surface walking-neural network method, we reveal all key metastable intermediates during the Ic-to-Ih phase transition, which are basically low-energy structural defects in ice, including vacancies, heterophase junctions, and stacking faults. This leads to the first identification of the lowest energy pathways from ice Ic to Ih, where the presence of vacancy defects in ice allows the transformation kinetically by initiating a fast Ih nucleation. The subsequent migration of a vacancy, with a barrier of 48 kJ/mol, turns out to be the rate-determining step in Ih phase growth,  \nrationalizing the unexpected prevalence of anisotropic stacking faults in low-temperature ice particles. This vacancy-controlled kinetics in Ih formation arises from the flexibility of the local geometry of a weaker H-bonding environment around the vacancy, which suggests that the frustrated material with a complex energy landscape may seek an unusual phase transition pathway with the help of a low level of heterogeneity.  \n1. INTRODUCTION  \nIce plays a basic role in the evolution of the universe. 1−3 The hexagonal phase, ice Ih, is the most stable phase upon freezing at ambient pressure or below, whereas the cubic phase, ice Ic, has recently been own to be a key metastable phase (35 J/ mol less stable at 170 K4,5) that crystalizes first fro water  \nand transforms irreversibly into ice Ih2−4,6 above 150 K (Figure 1). This crystal phase transition, being sensitive to ice microstructures, is central to natural phenomena ranging from cloud formation,7 to the dehydration of materials,8 and toozone depletion.9 Considerable efforts are therefore devoted to identifying ice defects (e.g., vacancies, heterophase junctions (HJ), and stacking faults) and understanding this transition kinetics. However, the atomic structure of ice defects remains largely elusive, which leads to a great difficulty in understanding their roles in phase transition kinetics and consequently some key properties of ice, such as roughness and environmental humidity.8−10  \nIt is known that an ice Ih crystal has a rhombic unit cell with four H2O molecules, and ice Ic has a cubic unit cell with eight molecules,1 as shown in Figure 1. For both crystals, the water molecules form layers consisting of six-membered puckered rings. Since the 1960s, extensive experimental studies7, 11−16 (e.g., using X-ray diffraction,11 differential thermal analysis,15  \nFigure 1. Perfect hexagonal and cubic ice crystals in ball-and-stick representation. Only the oxygen atoms are shown, which are interconnected by H-bondings, as dictated by the Bernal−Fowler rule. In ice Ih, each layer is a mirror image of the previous layer, whereas for ice Ic each successive layer is shifted a distance equal to half the diameter of the six-me","cbCaimOpnl8WB79L","https://ap.wps.com/l/cbCaimOpnl8WB79L","pdf",535792,1,"English","en",105,"# ABSTRACT\n# 1. INTRODUCTION","[{\"question\":\"What phases of ice are studied, and over what temperature range do they coexist?\",\"answer\":\"The study focuses on cubic ice (Ic) and hexagonal ice (Ih). They are reported to coexist over 150–240 K in ice particles.\"},{\"question\":\"How does the work reveal the Ic-to-Ih transition mechanism?\",\"answer\":\"It combines global sampling with a machine-learning potential using the stochastic surface walking-neural network method to identify metastable intermediates and low-energy pathways.\"},{\"question\":\"What role do vacancy defects play in Ih formation?\",\"answer\":\"Vacancy defects allow the transformation kinetically by initiating fast Ih nucleation, and vacancy migration with a 48 kJ/mol barrier is identified as the rate-determining step in Ih growth.\"}]","Two-Stage Solid-Phase Transition of Cubic Ice to Hexagonal Ice - Structural Origin and Kinetics | PDF",1787825024,20,{"code":4,"msg":30,"data":31},"ok",{"site_id":23,"language":22,"slug":32,"title":13,"keywords":33,"description":14,"schema_data":34,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":27},"two-stage-solid-phase-transition-of-cubic-ice-to-hexagonal-ice-structural-origin-and-kinetics","",{"@graph":35,"@context":85},[36,53,68],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,50],{"item":40,"name":41,"@type":42,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":49},"https://docshare.wps.com/document/research-report/",3,{"item":51,"name":13,"@type":42,"position":52},"https://docshare.wps.com/document/two-stage-solid-phase-transition-of-cubic-ice-to-hexagonal-ice-structural-origin-and-kinetics/150657/",4,{"url":51,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":22,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":40,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-09-04","2026-08-27",true,{"@type":65,"interactionType":66,"userInteractionCount":20},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"What phases of ice are studied, and over what temperature range do they coexist?","Question",{"text":75,"@type":76},"The study focuses on cubic ice (Ic) and hexagonal ice (Ih). They are reported to coexist over 150–240 K in ice particles.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"How does the work reveal the Ic-to-Ih transition mechanism?",{"text":80,"@type":76},"It combines global sampling with a machine-learning potential using the stochastic surface walking-neural network method to identify metastable intermediates and low-energy pathways.",{"name":82,"@type":73,"acceptedAnswer":83},"What role do vacancy defects play in Ih formation?",{"text":84,"@type":76},"Vacancy defects allow the transformation kinetically by initiating fast Ih nucleation, and vacancy migration with a 48 kJ/mol barrier is identified as the rate-determining step in Ih growth.","https://schema.org",{"og:url":51,"og:type":87,"og:title":13,"og:site_name":58,"og:description":14},"article",{"robots":89,"canonical":51},"index,follow",{"doc_id":7,"site_id":23},{"code":4,"msg":5,"data":92},[93,97,101,105,110,115,120,123,127,130,134],{"id":20,"doc_module":4,"doc_module_name":45,"category_name":94,"show_sort_weight":95,"slug":96},"Story & Novel",90,"story-novel",{"id":46,"doc_module":4,"doc_module_name":45,"category_name":98,"show_sort_weight":99,"slug":100},"Literature",80,"literature",{"id":52,"doc_module":4,"doc_module_name":45,"category_name":102,"show_sort_weight":103,"slug":104},"Exam",70,"exam",{"id":106,"doc_module":4,"doc_module_name":45,"category_name":107,"show_sort_weight":108,"slug":109},5,"Comic",60,"comic",{"id":111,"doc_module":4,"doc_module_name":45,"category_name":112,"show_sort_weight":113,"slug":114},6,"Technology",50,"technology",{"id":116,"doc_module":4,"doc_module_name":45,"category_name":117,"show_sort_weight":118,"slug":119},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":45,"category_name":12,"show_sort_weight":121,"slug":122},30,"research-report",{"id":124,"doc_module":4,"doc_module_name":45,"category_name":125,"show_sort_weight":28,"slug":126},9,"Religion & Spirituality","religion-spirituality",{"id":28,"doc_module":4,"doc_module_name":45,"category_name":128,"show_sort_weight":28,"slug":129},"World Cup","world-cup",{"id":131,"doc_module":4,"doc_module_name":45,"category_name":132,"show_sort_weight":131,"slug":133},10,"Lifestyle","lifestyle",{"id":135,"doc_module":4,"doc_module_name":45,"category_name":136,"show_sort_weight":106,"slug":137},19,"General","general"]